be all in somebody's/the mind

be all in (one's)/the mind

To exist solely in one's thoughts, rather than in reality. Don't tell me that my worries are all in my mind—you know this can be a dangerous area. Your presentation sounded great, honestly. Your fears are all in the mind.See also: all, mind

be all in somebody’s/the ˈmind

not be true or real; be imagined: She’s not really ill — it’s all in the mind.See also: all, mind